As I posted in another thread:
I used to keep budgies, which seemed very NT to me. Very chatty, into mutual preening, and if I put an untamed budgie into my very tame flock, it would become tame very quickly, as if trying to fit in. Then I added another breeding male to the aviary, and while there was nothing unusual about him, he had lots of babies and some of them had rather unusual behavioral characteristics. Some of them were hatched and raised by other parents, so it wasn't just him as a parent - I can only assume it was some sort of recessive gene. First I had one that was practically a psychopath - I had to give her away because she kept killing other budgies, and she took on a parrot...and won! Then there was a budgie who kept jumping off things and crash landing (she could fly absolutely fine) - she broke her leg doing that, but kept doing it! Then there was one who I would say HAD to be low-functioning autistic! Seemed completely unaware of the other budgies, ignored alarm calls and the like, but he wasn't blind or deaf or anything, and he never developed normal vocalisations, just kept making baby begging noises into adulthood. Last one I had was more than a little Aspie, so much so that even my Aspie boyfriend noticed him! Personal space issues (hated mutual preening, kind of tensed up and got stressed when another bird tried to touch him), got overheated easily, seemed to not get on too well talking to other budgies (he would go up to them and kind of hesitantly chatter, but without all the body language they communicate with, and the other bird would just ignore him. When he became an adult, he kept mostly to himself, but had just one friend, an old female who he kind of glued himself to), and not to mention, VERY intelligent!
I'm doing a veterinary science degree now, and I hope to someday study that for a phD or something. So you'll be pleased to know, if you're interested in this issue, you may have answers in a few years. SO dibs on that for a thesis - 'autism and PDDs in the domestic parakeet'.
The other thread was called "autism in other species".